Improvement in molds for casting steel



UNITED STATES- PATENT OFFICE.

JOHN DEERE, OF MOLINE, ILLINOIS.

IMPROVEMENT lN MOLDS FOR CASTING STEEL.

Specification forming part of Letters Patent No. 1,203, dated January12, 1864.

as the castings are formed with air spaces or cells, or blown, as it istechnically termed.

Dry-sand molds cannot be used, as the melted metal fuses and cuts awaythe inner surface of the mold, so that it will not produce a perfectcasting. Cast-iron molds have also been tried but these also are fusedor cut away by the melted steel, and also'produce blown castings, asthere is no ready escape for the air and gases during the advent of themelted steel into the mold. Imperfect steel castings therefore are nowquite commonly used.

By my invention 1 can produce perfect steel castings for the purposespecified with the greatest facility and without any greater expense, ornot appreciably greater than that attending ordinary iron castings insand molds.

To enable those skilled in' the art to fully understand and practice myinvention, I will proceed to describe it.

1 form a mold by means of a' suitable pattern out of dry sand in theusual way, and after the mold vis formed I coat its inner surface withblack-lead, (plumbago,) which may be moistened by water having a littlefire-clay dissolved in it. The sand also'used in forming the mold may betempered with fireclay water. This fire-clay waterhas atendency torender the sand and black-lead or plumba go rather more adhesive thanthey would be if water alone were used. After the mold is formed andcoated internally with the black-lead or plumbago, it is baked, say, forabout twelve hours, or until all moisture is thoroughly expelled fromit, and when thus baked and thoroughly dried the black-lead or plumbagowill form a hard crust, coat, or glazing for the inner surface of themold, so as to prevent the melted steel from coming in contact with thesand.

The latter therefore cannot be fused and cut may, before being baked anddried, be peril,

rated with vent-holes to admit of the escape of air and gases. I wouldfurther rema'rkthat the mold is used but for one casting only, it

being, after once used, broken up or pulverized and the same ingredientsused for the formation of another mold.

Having thus fully described my invention, what I claim therein as new,and desire to secure by Letters Patent, is-- For casting plow-plates orother articles of steel, the use of molds prepared as herein setforth-that is to say, the body of the mold formed of dry sand or loamand its internal surfacecoated with plumbago, both of which substances,previous to being used, to bemoistened with an aquous solution offire-clay, and the mold, when so made, to be thoroughly baked and driedin an oven or furnace, all substantially as and for the purpose hereindescribed.

JOHN DEERE.

Witnesses:

M. S. PARTRIDGE, M. M. LIVINGSTON.

